Kinetics of Phytoremediation of Petroleum Hydrocarbon ...agrologists, biologists, chemists,...

Kinetics of Phytoremediation of Petroleum Hydrocarbon Contaminated Soil

Elizabeth W. Murray, Bruce M. Greenberg*, Kent Cryer, Ben Poltorak, Justin McKeown,

Jess Spies, and Perry D. GerwingEarthmaster Environmental Strategies

and the *University of Waterloo

Earthmaster Environmental Strategies Inc.

A Canadian environmental technologies company:• Based in Calgary, Alberta.• Founded in 1998.• Specializes in providing environmental services to the

commercial/industrial and upstream oil and gas industry in Western Canada.

• Team of environmental consultants consisting of professional agrologists, biologists, chemists, ecologists, engineers, geoscientists, soil scientists, plant scientists, aquatic specialists, and foresters.

• Co-developed commercial phytoremediation systems (PEPSystems™) to treat contaminated soil in an eco-friendly and responsible manner.

Phytoremediation – How it Works

Rhizodegradation – Petroleum Hydrocarbons

Salt

• Improved rhizosphere– Soil– Organic matter– Bacteria– Water– Roots – Contaminants

• Phytostimulation– Petroleum Hydrocarbons

• Phytoextractionsoilrootfoliage

– Salts– Metals

Challenge – getting the plants to grow.

Presenter

Presentation Notes

Phytoremediation – use of plants PHC degradation is done by phytostimulation

Plant Growth Promoting Rhizobacteria (PGPR) -Enhanced Phytoremediation Systems

Presenter

Presentation Notes

We address the challenges of getting the plants to grow by using PEPSystems – see next slide for technology history

• Developed through collaboration between Dr. Bruce Greenberg of the University of Waterloo and Earthmaster for contaminated site clean-up.

• Earthmaster has assumed control of the PEPSystems technology and now manages all PGPR testing, selection, seed treating and overall site specific remediation system design in Calgary. Dr. Greenberg continues to collaborate on PEPSystems.

• The use of specific soil or plant associated microorganisms to enhance plant growth for a variety of applications is gaining popularity due to its effectiveness (agriculture).

• Earthmaster continues to conduct research on how to improve PEPSystems for remediation of contaminated sites or other applications such as to enhance plant growth on marginal or poor quality soils.

Presenter

Presentation Notes

Highlight that we are now solely responsible for all things PEPSystems related. Bruce is a consultant only – EM owns the technology.

PGPR – Facilitating Plant Growth in Challenging Conditions

Stress ethylene

Plant vigor

Root development

Rhizobacteria

Leaves

Salt and metals uptake

Degradation of PHC

Active rhizosphere:PGPR co-localize with developing roots

Presenter

Presentation Notes

This is how it works. PGPR co-localize with roots. Plant supports PGPR, PGPR provides ASS deaminase to break down ACC (ethylene precursor). This helps to alleviate plant stress to allow for growth in challenging conditions. Advantages: Cost effective Aesthetics - environmentally friendly Reduces landfill waste Fine roots of plants are effective at binding and transforming PHC. F2, F3 and F4 doesn’t work with conventional bioremediation using fertilizer and organic matter followed by tilling. Plants make it better for complex PHC and the stricter regulatory guidelines now required.

PHC contamination in soil from leaks and spills• Carcinogen, mutagen, and is an neurotoxic organic pollutant.• Current treatment/disposal methods include: Incineration/thermal – toxic by-products, soil damage Disposal at a landfill – $$, liability, loss of soil Mechanical methods – soil mixing/tillage Chemical methods – not always effective, can be expensive

• PHC is prone to degradation by bacteria which makes it an excellent candidate for bioremediation. Must have bacteria that have the appropriate metabolic capabilities

(Pseudomonads are a good choice – produce rhamnolipids). Must establish and maintain conditions that favor enhanced oil

biodegradation rates in the contaminated environment – fertilizer use.

Petroleum Hydrocarbon (PHC) in Soil

Presenter

Presentation Notes

Rhamnolipids are biosurfactants produced by Pseudomonads that can make PHC more available to the microbes. PHC can bind soil particles and be hard to access by bacteria.

Goal: to predict the amount of time it takes PEPSystems to degrade PHC in soil based on starting concentrations and desired end point.

• Kinetic equations developed in 2015 by Dr. Bruce Greenberg using data from six phytoremediation sites in Alberta.

• Based on PHC fractions F2(C10-16) & F3(C16-34) remediation kinetic data.

• Observed 25-35 % remediation per year for both PHC fractions.• The remediation rates followed first order exponential decay

kinetics.

Predictive Kinetic Equations for PHC Remediation

Presenter

Presentation Notes

Bruce published this in Canadian Reclamation in 2015

F2 Remediation Trend

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Presentation Notes

F2 kinetic equation

F3 Remediation Trend

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Presentation Notes

F3 kinetic equation

Predictive kinetic equations are based on whole site averages. Limitations include:

• Heterogeneous soil containing ‘hot spots’ which may require additional treatment time

• Lack of precipitation or very low soil moisture• Poor agronomic practices• Treatment zone thickness of 0.30 m• Rooting depth of 0.30 m corresponding to treatment depth• Extremely high PHC levels (F3 of >10,000 mg/kg) not tested

Limitations of the Kinetic Equations

Presenter

Presentation Notes

Phyto is a biological system so it is prone to any factors that can impact bacteria and plant health. Note that the system can only treat as deep as the roots go.

Site 1 – West Central Alberta 14-19

12,000 m³ of material excavated from 2 former DWDAs, wellbore area, and disturbed area were spread to a depth of 1 m:

• Land use – natural• Soil texture – fine• AB remediation guideline values F2:

• surface soil – 150 mg/kg• subsoil – 300 or 1000 mg/kg

• Seed – Arg, Prg, TF• PGPR – Pseudomonas sp.• Lift #1 T=0 October 2013

• stripped 4000 m³ (to 0.25 or 0.50 m depth) in Mar 2016

• Lift #2 T=0 October 2016• includes hot spots from lift #1• treatment is ongoing

Presenter

Presentation Notes

Go over the features of a typical soil treatment facility: sump, channels, clay liner, clean topsoil (green) and overburden (red) stockpiles, control area Permanent sample points: small (<3000m³) 6 pts, med (3-10,000m³) 1 every 500m³, >10,000 m³, 1 every 1000m³ composite of 3 cores within 1 m radius. UW3/4 isolated in southern Ontario by Bruce. 12,000 m³ of soil containing PHC fractions F1 to F3, benzene, ethylbenzene, xylenes, arsenic, lead, and molybdenum exceedances


range average*

0.00-0.25 m F2 9 of 11 54-540 310 ± 46

0.25-0.50 m F2 9 of 11 41-790 342 ± 76# samples exceeding surface soil guideline value*average mg/kg ± standard error

Lift #1 Sample Chemistry T = 0

Depth PHC # samples

Oct 2013

range average*

0.00-0.25 m F2 5 of 11 59-790 270±78

0.25-0.50 m F2 10 of 11 110-1300 333±102


Depth PHC # samples

Nov 2016

Lift #2Depth T=0 C0 x yrs C0.25 yrs

0.00-0.25 m 270 1.3 1150.25-0.50 m 333 1.8 212


0.00-0.25 m 310 1.6 660.25-0.50 m 342 1.8 126

Presenter

Presentation Notes

Explain how treatment works – timing based on growing seasons and when the site can be accessed.


10,000 m³ of material excavated from a former drilling waste disposal area and earthen pit were spread to a depth of 1 m:



• Seed – Arg, Prg, TF• PGPR – Pseudomonas sp.• Lift #1 T=0 October 2013

• stripped 3500 m³ (to 0.25 or 0.50 m depth) in Mar 2016

• Lift #2 T=0 October 2016• includes hot spots from lift #1• treatment is ongoing

Presenter

Presentation Notes

Location - 37 km NW of Edson. 10,000 m³ of soil containing SAR, PHC fractions F1 to F3, benzene, toluene, ethylbenzene, xylenes, and lead. Lift #2 contains hot spots from Lift #1


range average*

0.00-0.25 m F2 13 of 20 66-830 311 ± 58

0.25-0.50 m F2 15 of 20 60-1500 403 ± 75

Depth PHC # samples


*average mg/kg ± standard error# samples exceeding surface soil guideline value

Oct 2013


0.00-0.25 m 311 1.6 1380.25-0.50 m 403 2.2 336

range average*

0.00-0.25 m F2 7 of 20 21-520 161±30

0.25-0.50 m F2 14 of 20 10-1100 417±78


Depth PHC # samples

Nov 2016


0.00-0.25 m 161 0.2 2530.25-0.50 m 417 2.3 247

y/Co = e-0.45x150 mg/kgPredicted # of years

1300 mg/kg-0.24 for F3

Presenter

Presentation Notes

Co = starting concentration – whole site average Y = desired remediation guideline value 150 mg/kg for surface soil, fine grain, natural land use X = predicted years to reach y Lift #1 seeded Oct2013, phyto starts May2014 with germination, sampled Nov2015 so 19 months or 1.6 y Striped Mar2016, Lift #2 re-spread and sampled Oct2016, phyto starts May2017, test Jul2017 so 3 months or 0.25 y

Site 3 – Red Earth 02-31

2,950 m³ of material from former emulsion spills were spread to a depth of 0.45 m:



• AB remediation guideline values F3:• surface soil – 1300 mg/kg• subsoil – 2600 or 3500 mg/kg

• Seed – Arg, Prg, TF• PGPR – Pseudomonas sp.• Lift #1 T=0 Oct 2011, used to generate equation

Lift #1Depth PHC T=0 C0 C2.5 yrs

0.00-0.20 m 752 1650.20-0.40 m 906 1100.00-0.20 m F3 1740 884

F2

Presenter

Presentation Notes

The next 3 sites are active sites used to treat the same stockpile of contaminated soil. Salt and PHC impacted soil – no success with other treatments phyto Lift #1 was used to generate the original 2015 kinetic equation We had the option of burying the soil as subsoil so could treat to that remediation guideline value


2,750 m³ of lift #1 was stripped and placed into stockpiles complying with either surface soil or subsoil criteria.200 m3 of contaminated soil was re-spread to create lift #2:

• Lift #2 T=0 August 2015• includes any hot spots from lift #1• treatment is completed

Lift #2Depth PHC T=0 C0 x yrs C1.1 yrs

0.00-0.20 m F2 204 0.7 23

# surface # subsoil range average*

0.00-0.20 m F2 1 of 3 0 of 3 41-420 204±113

# samples exceeding surface soil guideline value

*average mg/kg ± standard error


Depth PHCsamples Aug2015




0.00-0.20 m 620 1670.20-0.40 m 702 2300.00-0.20 m 1537 10610.20-0.40 m 1423 833

F3

F2










0.00-0.20 m F2 612 3.1 820.00-0.20 m F3 1686 0.6 556


0.00-0.20 m F2 4 of 5 1 of 5 78-1600 612±261

0.00-0.20 m F3 3 of 5 0 of 5 530-3400 1686±482# samples exceeding surface soil guideline value*average mg/kg ± standard error


Depth PHCsamples Aug2015









0.00-0.20 m 916 1060.20-0.40 m 826 2210.00-0.20 m F3 2394 925

F2





0.00-0.20 m F2 669 3.3 660.00-0.20 m F3 2093 1.1 459


F2 6 of 8 3 of 8 62-1400 669±196F3 5 of 8 3 of 8 230-4000 2093±570

samples

0.00-0.20 m

# samples exceeding surface soil guideline value*average mg/kg ± standard error


Depth PHCAug2015

Presenter

Presentation Notes

Stockpiles from stripping were piled according to surface or subsoil criteria compliance As of August 2016, all samples comply with surface soil criteria Site is now ready to close


Site 6 – NWT C-17

Approximately 5,800 m³ of material excavated from former pits and sumps onsite to be treated for PHC contamination resulting from historical drilling activities:

• Land use – industrial• Soil texture – course• CCME remediation guideline values F2:

• surface soil – 260 mg/kg• subsoil – 320 mg/kg

• Seed – Arg, Prg, TF• PGPR – Pseudomonas corrugata and P.

marginalis.• Lift #1 T=0 June 2008

• Surface soil treated for salt and PHC.• Completed in July 2011 and left in place.• Additional material excavated and placed on

top of Lift #1 for treatment.

Presenter

Presentation Notes

C-17 is ~40 km southeast of Norman Wells Site drilled in 1997 Lift #1 – surface soil treated as is for mostly salts. First 2 lifts treated by Bruce’s group. EM took over in 2015 at the end of lift #3 treatment

Site 6 – NWT C-17


0.00-0.30 m 549 1.7 84


0.00-0.30 m 1417 3.8 275


0.00-0.30 m 644 2.0 360

Lift #3: 900 m³ spread on lift #2. Treated for F2 contamination.

Lift #4: 1,600 m³ spread on Lift #3. Treated for F2 contamination and 1250 m³ stripped in June 2017.

Lift #5: 350 m³ mixed with 750 m³ of additional soil. Treated for F2 contamination starting June 2017.

Presenter

Presentation Notes

Lift #2 Jul2011-Sep2013 and left in place – F2 Lift #3 Sep2013- Jun2016 and left in place – F2 Lift #4 Jun2016-Jun2017 1250 m³. Soil meeting criteria was stripped in June 2017 and placed in the holes. The remaining (350 m³) was added to 750 m³ to make Lift #5.

Jun2016

Site 6 – NWT C-17 Challenges

Presenter

Presentation Notes

There are challenges in phytoremediation, especially when working on remote sites were returning at a later time in the season is $$$ so the work needs to get done then and now.


Sep2016

Presenter

Presentation Notes

Result of poor conditions when seeding – leads to areas of poor growth.


# samples range average* # samples range average*

0.00-0.30 m F2 23 of 25 57-1350 644±73 12 of 25 50-802 360±45# samples exceeding surface soil guideline value*average mg/kg ± standard error

Depth PHCJul 2016 Sep 2016


Presenter

Presentation Notes

Poor growth gives poor remed. – shows need for PGPR/plant cooperation for PEPSystems to be the most effective. Samples exceed in June but comply in Sep: 10, 11, 13, 14, 15, 16, 20 Samples exceed in June and Sep: 1, 2, 3, 4, 5, 6, 7, 8, 9, 21, 24, 25 Only ones complying at both times: 12 and 23

Site 6 – NWT C-17

Presenter

Presentation Notes

September 2017 avg. F2=152 mg/kg Treatment lift #5 – 1100 m³ successfully remediated. Site ready for closure

Site 7 – NWT C-49

A small burn area on a remote exploratory wellsite showed F2 and F3 concentrations that exceeded the CCME remediation guideline values:

• Land use – industrial or parkland• Soil texture – fine• CCME remediation guideline values F2:

• industrial soil – 260 mg/kg• parkland soil – 150 mg/kg

• CCME remediation guideline values F3:• industrial soil – 1700 mg/kg• parkland soil – 1300 mg/kg

• Seed – Arg, Prg, TF• PGPR – Pseudomonas sp.• In situ T=0 July 2013

Presenter

Presentation Notes

One of 2 sites (lease and sump) that were fly in only in the NWT 170 km northeast of Norman Wells. Mostly had salt contamination but a small burn area had PHC F2 and F3 Compared to both industrial (more forgiving) and parkland criteria CCME Canadian Council of Ministers of the Environment

Site 7 – NWT C-49


0.00-0.25 m 208 0.7 550.25-0.50 m 858 3.9 10

range average*

0.00-0.25 m F2 1 of 3 10-600 208±196

0.25-0.50 m F2 2 of 3 25-2400 858±772# samples exceeding surface soil guideline value*average mg/kg ± standard error

In situ Sample Chemistry T = 0

Depth PHC # samples

Jul 2013

Presenter

Presentation Notes

Point out the 3 worked areas and the burn area on left

Predictive Equation Summary F2

site layer # depth C0 goal predicted yrs Cend actual yrs notes0.00-0.25 m 310 1.6 66 0.90.25-0.50 m 342 1.8 126 2.40.00-0.25 m 270 1.3 115 0.70.25-0.50 m 333 0.2 212 0.70.00-0.25 m 311 1.6 138 1.60.25-0.50 m 403 2.2 336 1.6 removed before complete

0.00-0.25 m 161 0.2 253 0.7 removed before complete

0.25-0.50 m 417 0.7 247 0.73 2 0.00-0.20 m 204 150 0.7 23 1.0 no spring assessment4 2 0.00-0.20 m 612 150 3.1 82 1.05 2 0.00-0.20 m 669 150 3.3 66 1.0

2 0.00-0.30 m 549 1.7 84 2.03 0.00-0.30 m 1340 2.1 275 2.04 0.00-0.30 m 644 2.1 360 0.35 0.00-0.30 m 381 0.9 152 0.3

0.00-0.25 m 208 0.7 55 1.0 no spring assessment0.25-0.50 m 858 2.7 10 0.3

8 1 0.00-0.30 m 343 150 1.8 335 1.0 project terminated

9 1 0.25-0.50 m 512 150 2.7 309 1.3 project terminated467 1.7 171 1.1 all layers

497 1.6 147 1.1 all completed layers

11

150 or 300

2

21

150 or 300

2

6260 or

520

7 1 260

19 layers15 layers

Presenter

Presentation Notes

About 35% faster than predicted 336 failure – lack of oxygen to deeper layer? 253 failure – sample variability in initial sampling? No spring assessment – could have been completed in the spring if tested

Predictive Equation Summary F3

Conclusions:• The predictive equations are conservative and remediation is almost always

achieved before the predicted amount of time.• Number of growing seasons is a better timeline to work with.

Often seeding is done in the fall which will increase the # of following year growth season months.

site lift # depth C0 goal predicted yrs Cend actual yrs notes4 2 0.00-0.20 m 1686 1300 0.6 556 1.05 2 0.00-0.20 m 2093 1300 1.1 459 1.08 1 0.00-0.30 m 1950 1300 1.7 1300 1.7

0.00-0.25 m 1714 1.6 1399 1.0 project terminated0.25-0.50 m 3885 3.9 2657 1.3 project terminated0.00-0.25 m 2267 2.7 1786 1.3 project terminated

0.25-0.50 m 1881 2.5 1096 1.0 project terminated2211 2.0 1322 1.2 all layers

1903 1.5 853 1.2 all completed layers

1300

10 1 1300

7 layers4 layers

9 1

Presenter

Presentation Notes

About 20% faster than predicted

• Used data collected from commercial phytoremediation programs over last 6 years.

• Starting F2 concentrations (C0) for the updated kinetic equation data ranged from 400-600 mg/kg with an average of 526 mg/kg.

• The target remediation guideline value (y) was 150 mg/kg with the exception of one northern site which had a target remediation guideline value of 260 mg/kg.

• F2 revised: y = C0e−0.624x

• Insufficient data was available to update the F3 kinetic equation.

Revised PHC Fraction F2 Predictive Equation

Revised PHC Fraction F2 Equation

Presenter

Presentation Notes

About 35-40% faster than original predictive equation for F2 Variability around the middle data point is because there were only 2 samples

Bear Rock Sinkhole NWT

Presenter

Presentation Notes

The absolutely amazing views when working in remote areas of Canada Caused by the collapse of a subterranean cave

National Research Council – Industrial Research Assistance Program (IRAP).Clients who have allowed Earthmaster to conduct field trials to advance the PEPSystems technology.

Come visit us: at the Earthmaster booth

www.earthmaster.ca

Acknowledgements

Thank YouQuestions?

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Kinetics of Phytoremediation of Petroleum Hydrocarbon ...agrologists, biologists, chemists,...

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